1. Field of the Invention
This invention relates to textile lubricants and is more particularly concerned with random copolymers of polyoxyethylene polyoxypropylene glycol monoester and a process of producing the same. The invention is also concerned with a lubricated synthetic fiber.
2. Description of the Prior Art
I am aware of U.S. Pat. No. 3,770,701, U.S. Pat. No. 2,620,304 and U.S. Pat. No. 2,457,139 which I consider to be the most pertinent references. I am the co-inventor of the surfactant described in U.S. Pat. No. 3,770,701.
It is well-known that essentially all synthetic textile fibers as originally produced cannot be processed into yarn and fabric in textile mills because of snagging, clinging and breaking that results from a lack of lubrication and/or static electricity. These processing difficulties, however, are usually overcome by the application of "textile lubricants" or "fiber finishes" to the fibers.
The traditional fiber finishes used on synthetic textile fibers are made up of three components. The first ingredient is the basic lubricants. Most widely used for the lubricant is either a mineral oil or a fatty ester (e.g. butyl stearate). The second ingredient is an antistatic agent to reduce static electricity which is common to nearly all synthetic fibers and especially those with low moisture regain properties. Anti-static agents are generally of the cationic (quaternary amine or imidazolinium salts) or anionic type (salts of partial esters of phosphoric acid). The third ingredient, is the emulsifying agent. It is necessary to use an emulsifying agent since an even application of finish components is best achieved from a dilute aqueous emulsion. Emulsifying agents commonly employed are nonionic (polyoxyethylene ethers and esters) or anionic (salts of akyarylsulfonic acids). The patent to Fortess, et al, U.S. Pat. No. 2,730,498 discloses a typical finish.
The lubricants used heretofore have many drawbacks, but chief among them is their volatility. In other words lubricants have objectionable vapors which are released in the area around the yarn or fiber drying equipment.
Water insolubility of mineral oil and fatty ester lubricants is another problem. When a lubricant is water insoluble it is usually difficult to apply to the fiber. To overcome this, the lubricant is emulsified with the water. The nonuniformity and instability of these emulsions frequently results in the uneven application of the lubricant to the fibers. Processing problems usually result from this uneven application. Even when excellent emulsions are prepared, the relatively large proportion of emulsifying agent necessary in the emulsion has a negative effect on the lubrication of the fibers.
Another problem with oily lubricants is that they are difficult to remove from the fibers after these fibers have been processed into textile yarn or fabric. The scouring of these oil bearing fabrics must be thorough and complete since spotty and uneven dyeing of the fabrics and poor hand characteristics will result.
Still another problem is that the lubricant must be disposed of after it is scoured off. Disposal, by way of sewering at the textile mill, results in an oil film or slick in nearby streams and ponds. This oil is only very slowly decomposed by bacteria, if at all.
In the past, attempts have been made to overcome the problems described above by using fatty esters of polyoxyethylene glycols, as the lubricants or emulsifiers. These attempts have met with limited success in some special circumstances. The failure of these products to completely resolve the difficulties, results from the nature of the materials involved. In order to achieve good lubrication from the fatty acid portion of the product, it is necessary for the fatty hydrocarbon chain be as long as feasible, at least eight carbons long and preferably greater than twelve. In order to make esters of such acid water soluble, it is necessary to employ proportionately longer polyoxyethylene glycol chains. This results in pasty solid products or high viscosity liquids which are too thick for use in the high speed processing of textile fibers.
Surfactants and lubricants are known having an aliphatic alcohol or carboxylic acid and a series of oxyethylene groups, as for example U.S. Pat. No. 2,457,139 to Fife, et al. However, such compounds are generally speaking unsatisfactory for high-speed textile fabrication uses, either because they are water insoluble or too viscous or have insufficient hydrocarbon chain content. The problems described above are believed to be overcome by the lubricants of the present invention.